In the realm of quantum computing, maintaining quantum bits (qubits) at extremely low temperatures, close to absolute zero (-273°C), is essential. This cooling minimizes atomic motion and reduces noise. However, the electronics that manage these quantum circuits generate heat, which is challenging to dissipate at such low temperatures. To address this, current technologies typically separate quantum circuits from their electronic components, leading to inefficiencies and noise that hinder the scalability of quantum systems beyond the laboratory setting.

Figure 1. The 2D Device. (Credit: Alain Herzog)

A team of researchers from EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES), led by Andras Kis at the School of Engineering, has made a significant breakthrough. They have developed a device that operates efficiently at ultra-low temperatures, comparable to current technologies at room temperature. Figure 1 shows the LANES lab's 2D device made of graphene and indium selenide.

“We are the first to create a device that matches the conversion efficiency of current technologies but operates at the low magnetic fields and ultra-low temperatures required for quantum systems. This work is truly a step ahead,” says LANES PhD student Gabriele Pasquale [1].

This groundbreaking device leverages the exceptional electrical conductivity of graphene combined with the semiconductor properties of indium selenide. Only a few atoms thick, it functions as a two-dimensional object. This innovative combination of materials and structure delivers unprecedented performance, as detailed in a publication in Nature Nanotechnology.

Harnessing the Nernst Effect

The device utilizes the Nernst effect, a complex thermoelectric phenomenon that generates an electrical voltage when a magnetic field is applied perpendicular to an object with a temperature gradient. The two-dimensional nature of this device allows for precise electrical control of this mechanism.

Fabricated at the EPFL Center for MicroNanoTechnology and the LANES lab, the device was tested using a laser as a heat source and a specialized dilution refrigerator to reach 100 millikelvin—colder than outer space. Converting heat to voltage at such low temperatures is typically extremely challenging, but the novel device successfully harnesses the Nernst effect to achieve this, filling a critical gap in quantum technology.

“If you think of a laptop in a cold office, the laptop will still heat up as it operates, causing the room temperature to rise. In quantum computing systems, there is currently no mechanism to prevent this heat from disturbing the qubits. Our device could provide this necessary cooling,” explains Pasquale [2].

As a physicist, Pasquale highlights the significance of this research in advancing the understanding of thermopower conversion at low temperatures—an area previously underexplored. With its high conversion efficiency and potentially manufacturable electronic components, the LANES team believes their device could be integrated into existing low-temperature quantum circuits.

“These findings represent a major advancement in nanotechnology and hold promise for developing advanced cooling technologies essential for quantum computing at millikelvin temperatures,” Pasquale adds. “We believe this achievement could revolutionize cooling systems for future technologies.”

Source: EPFL

References:

1. https://thequantuminsider.com/2024/07/06/a-2d-device-may-help-quantum-computers-stay-cool/
2. https://interestingengineering.com/innovation/2d-device-keep-quantum-computers-cool

Cite this article:

Hana M (2024), Cooling Quantum Leap: EPFL’s Breakthrough Device Could Revolutionize Quantum Computing, AnaTechMaz, pp. 142